We used the Heathrow Hoppa from the Renaissance Hotel, the service was fine running from the hotel to the airport however the return journey was not good. There was no clear instructions of where to catch one of the buses from so we ended up walking up and down trying to decide which stop to wait at. One gentleman said he'd been waiting for over an hour and no bus had arrived. Others gave up and went for taxis. We waited over half an hour for a bus to arrive, which should have been every 15 minutes and when it did arrive it was jammed full of people with luggage all over the place, which looked dangerous. We were told that no one could get on, however rather than drive away the driver seemed to want to have a debate with everyone stood in the queue! Unbelievable! We definitely WILL NOT be using these again. Don't waste your money and risk missing your flight or been stranded on your return! This was booked via Holiday Extras.